Speedlights don't weigh very much, so it's not a matter of how much weight the stand can hold...but it's more a factor of what your uses are and what is convenient for you.
If you are using it for on-location work, you might not want a really heavy stand and might prefer one that is lighter and easier to carry. In a studio, you might want very sturdy, so that it can hold anything you might put on it. Or on the other hand, you might not have a lot of space, so you would want one with a small foot print (at the cost of being less sturdy).
Maybe you want one that is really high, or maybe not. Maybe you want on with more sections, so that it collapse down smaller for easy transport.

Also, to mount a speedlight, you will need some sort of adapter. The Canon 580EX comes with a 'foot' that will hold the flash and has 1/4" thread on the bottom, which make it easy to mount to a tripod or light stand (with 1/4" stud).
Another popular method is with an umbrella adapter. Impact | Umbrella Bracket | 3117 | B&H Photo Video

I'm eventually getting one or two of these to supplement/replace what I have: LumoPro LP604 5-Section 6ft Stand It's a good price for a portable 5 section. I figure if I am going the strobist route that portability is a plus.

Yes, definitely portable, at only 30 inches in length when collapsed. You really will appreciate having the 8.5 foot height stands instead of shorties in the 6.5 foot range. The weight on those is not too bad either, and the price seems pretty reasonable these days at just under $30 per stand.